Electrode semiconductor workpiece holder and processing methods

ABSTRACT

A semiconductor workpiece holder for use in processing a semiconductor workpiece includes a workpiece support operatively mounted to support a workpiece in position for processing. A finger assembly is operatively mounted upon the workpiece support and includes a finger tip. The finger assembly is movable between an engaged position in which the finger tip is engaged against the workpiece, and a disengaged position in which the finger tip is moved away from the workpiece. Preferably, at least one electrode forms part of the finger assembly and includes an electrode contact for contacting a surface of said workpiece. At least one protective sheath covers at least some of the electrode contact. According to one aspect of the invention, a sheathed electrode having a sheathed electrode tip is positioned against a semiconductor workpiece surface in a manner engaging the workpiece surface with said sheathed electrode tip. A seal is formed about the periphery of the electrode tip, and with the electrode tip engaging the workpiece, a desired electrical contact is made to the workpiece. Thereafter, the workpiece is exposed to desired semiconductor processing conditions.

TECHNICAL FIELD

[0001] This invention relates to semiconductor workpiece holders andmethods for use in processing semiconductor workpieces.

BACKGROUND OF THE INVENTION

[0002] Semiconductor workpieces, such as semiconductor wafers and thelike, are the subject of extensive processing which most often involvessome type of automated or computer controlled processing. In processingsemiconductor workpieces it is often desirable to minimize the amount ofhuman contact to which a particular workpiece is exposed. Such reducesthe chances of an inadvertent contamination which could render theworkpiece useless.

[0003] Often times during processing, it is necessary to treat aparticular workpiece or workplace surface with chemicals, either gaseousor liquid. Such treatment allows for films or layers of material to bedeposited or grown on a workpiece surface. One method of accomplishingthis is to expose the particular workpiece to desired processingenvironments in which desired chemicals are present to form or grow suchfilms or layers. Some processing regimes involve moving the workpiecewithin the processing environment to effectuate film or layer coverage.Other processing regimes involve forming layers on or over a workpieceutilizing various electroplating techniques.

[0004] The above-described processing scenarios pose, among otherchallenges, a two-fold challenge. First, a challenge exists to reducethe amount of human contact with a semiconductor workpiece which isundergoing processing. Second, during such processing, challenges existrelating to the treatment of semiconductor workpieces during the variousprocessing stages. For example, in the above described processingcontext in which a workpiece is exposed to and moved within a processingenvironment, challenges exist which relate to transferring the workpieceinto the environment, effectively holding or maintaining the workpiecewithin the environment during processing, and moving the workpiece outof the environment at the conclusion of a particular processing stage.With respect to the semiconductor processing steps which utilizeelectroplating techniques, challenges exist which relate to effectivelyholding or maintaining the workpiece in a processing environment while adesired electrical bias is imparted to the workpiece.

[0005] The prior electroplating semiconductor processing equipment hasalso suffered some difficulty in that providing electrical contactbetween the electrodes and wafers has frequently led to the buildup ofplating material deposits at the point of contact. This deposits can beproblematic in subsequent processing steps and lead to defects in theresulting integrated circuits or other devices being made. Thus improvedelectrode constructions are needed to address this deficiency.

[0006] This invention grew out of the need to provide improvedsemiconductor processing devices and methods which effectively andefficiently hold or maintain workpieces within particular processingenvironments, including processing environments in which electroplatingof workpieces takes place.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Preferred embodiments of the invention are described below withreference to the accompanying drawings, which are briefly describedbelow.

[0008]FIG. 1 is an environmental view of the semiconductor processinghead of the present invention showing two processing heads in aprocessing station, one in a deployed, “closed” or “processing”position, and one in an “open” or “receive wafer” position.

[0009]FIG. 2 is an isometric view of the semiconductor processing headof the present invention.

[0010]FIG. 3 is a side elevation view of the processing head of thepresent invention showing the head in a “receive wafer” position.

[0011]FIG. 4 is a side elevation view of the processing head of FIG. 3showing the head in a rotated position ready to lower the wafer into theprocessing station.

[0012]FIG. 5 is a side elevation view of the processing head of FIG. 3showing the head operator pivoted to deploy the processing head andwafer into the bowl of the processing station.

[0013]FIG. 6 is a schematic front elevation view of the processing headindicating the portions detailed in FIGS. 7 and 8.

[0014]FIG. 7 is a front elevation sectional view of the left half of theprocessing head of the apparatus of the present invention also showing afirst embodiment of the wafer holding fingers.

[0015]FIG. 8 is a front elevation sectional view of the left half of theprocessing head of the apparatus of the present invention also showing afirst embodiment of the wafer holding fingers.

[0016]FIG. 9 is an isometric view of the operator base and operator armof the apparatus of the present invention with the protective coverremoved.

[0017]FIG. 10 is a right side elevation view of the operator arm of thepresent invention showing the processing head pivot drive mechanism.

[0018]FIG. 11 is a left side elevation view of the operator arm of thepresent invention showing the operator arm drive mechanism.

[0019]FIG. 12 is schematic plan view of the operator arm indicating theportions detailed in FIGS. 13 and 14.

[0020]FIG. 13 is a partial sectional plan view of the right side of theoperator arm showing the processing head drive mechanism.

[0021]FIG. 14 is a partial sectional plan view of the left side of theoperator arm showing the operator arm drive mechanism.

[0022]FIG. 15 is a side elevational view of a semiconductor workpieceholder constructed according to a preferred, aspect of the invention.

[0023]FIG. 16 is a front sectional view of the FIG. 1 semiconductorworkpiece holder.

[0024]FIG. 17 is a top plan view of a rotor which is constructed inaccordance with a preferred aspect of this invention, and which is takenalong line 3-3 in FIG. 16.

[0025]FIG. 18 is an isolated side sectional view of a finger assemblyconstructed in accordance with a preferred aspect of the invention andwhich is configured for mounting upon the FIG. 17 rotor.

[0026]FIG. 19 is a side elevational view of the finger assembly of FIG.18.

[0027]FIG. 20 is a fragmentary cross-sectional enlarged view of a fingerassembly and associated rotor structure.

[0028]FIG. 21 is a view taken along line 7-7 in FIG. 4 and shows aportion of the preferred finger assembly moving between an engaged anddisengaged position.

[0029]FIG. 22 is a view of a finger tip of the preferred finger assemblyand shows an electrode tip in a retracted or disengaged position (solidlines) and an engaged position (phantom lines) against a semiconductorworkpiece.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] This disclosure of the invention is submitted in furtherance ofthe constitutional purposes of the U.S. Patent Laws “to promote theprogress of science and useful arts” (Article 1, Section 8). TABLE 1Listing of Subsections of Detailed Description and Pertinent Items withReference Numerals and Page Numbers Workpiece Support 8 semiconductorprocessing machine 400 8 workpiece supports 401 8 Workpiece support 4028 Workpiece support 403 8 semiconductor manufacturing chamber 8 404 beamemitter 81 8 operator base 405 8 processing head 406 8 operator arm 4078 wafer holder 408 8 fingers 409 8 Workpiece holder 408 8 workpiece spinaxis 410 8 process pivot axis 411 8 operator pivot axis 412 9 workpieceW 9 fingertips 414 9 9 processing bowl 417 9 left and right forks 418and 419 10 Operator Base 11 operator base back portion 420 11 operatorbase left yoke arm 421 11 operator base right yoke arm 422 11 yoke armfasteners 423 11 operator arm bearings 424 11 operator arm 425 11Operator Arm 11 process arm rear cavity 426 12 lift motor 452 12 rotatemotor 428 12 processing head left pivot shaft 429 12 processing headright pivot shaft 430 12 Operator Arm-Processing Head Rotate Mechanism12 Processing head rotate mechanism 431 13 rotate shaft 432 13 securingcollar 433 13 rotate motor support 434 13 rotate encoder 435 13 rotatepulley inboard bearing 436 14 rotate belt 437 14 processing head pulley438 14 rotate belt tensioner 439 15 tensioner hub 468 15 processing headshaft bearing 440 15 processing head rotate bearing 469 15 processinghead shaft bearing 441 15 cable brackets 442 and 443 16 rotateovertravel protect 444 16 rotate flag 447 17 Rotate optical switches 445and 446 17 Operator Arm-Lift Mechanism 17 operator arm lift mechanism448 17 lift motor shaft 454 18 lift gear drive 453 18 lift drive shaft456 18 lift bushing 449 18 anchor plate 458 18 anchor fasteners 457 1818 Lift bearing 450 18 lift bearing support 460 19 operator arm frame461 19 lift anchor 451 19 lift overtravel protect 462 19 lift opticalswitch low 463 20 lift optical switch high 464 20 lift flag 465 20 liftmotor encoder 455 20 lift motor 452 20 slotted lift flag mounting slots467 20 lift flag fasteners 466 20 Processing Head 21 processing headhousing 470 21 circumferential grooves 471 21 rotate shaft openings 474and 475 21 left and right processing head mounts 21 472 processing headdoor 476 21 processing head void 477 22 Processing Head Spin Motor 22workpiece holder 478 22 spin axis 479 22 spin motor 480 23 top motorhousing 481 23 spin motor shaft 483 23 workpiece holder rotor 484 23 23rotor hub 485 23 rotor hub recess 486 23 workpiece shaft snap-ring 48823 rotor recess groove 489 23 spin encoder 498 24 optical tachometer 49924 Processing Head Finger Actuators 26 Pneumatic piston 502 27 actuatorspring 505 27 cavity end cap 507 27 retaining ring 508 27 pneumaticinlet 503 27 pneumatic supply line 504 27 actuator plate 509 27 actuatorplate connect screw 510 27 Wave springs 529 27 bushing 512 27 pneumaticpiston recess 511 27 finger actuator contacts 513 28 Processing HeadWorkpiece Holder 28 finger actuator lever 514 28 finger stem 515 29finger diaphragm 519 29 workpiece holder rotor 484 29 finger opening 52129 rotor diaphragm lip 523 29 finger spring 520 29 finger actuator tab522 29 finger collar or nut 517 29 518 29 finger actuator mechanism 50030 cavity 501 30 Semiconductor Workpiece Holder - ElectroplatingEmbodiment 30 semiconductor workpiece holder 810 30 bottom half or bowl811 31 Processing Head and Processing Head Operator 31 workpiece support812 31 spin head assembly 814 31 lift/rotate assembly 816 31 motor 81832 rotor 820 32 rotor spin axis 822 32 finger assembly 824 33 actuator825 33 rotor center piece 826 33 spokes 828 33 rotor perimeter piece 83033 Finger Assembly 34 finger assembly frame 832 35 angled slot 832a 35finger assembly frame outer flange 834 35 inner drive plate portion 83635 Finger Assembly Drive System 35 bearing 838 36 collet 840 36 bearingreceptacle 839 36 spring 842 36 spring seat 844 36 Finger AssemblyElectrical System 37 pin connector 846 37 finger 848 37 nut 850 37anti-rotation pin 852 37 finger tip 854 38 electrode contact 858 38Finger Assembly Drive System Interface 38 finger actuator 862 38 863 39first movement path axis 864 39 secondary linkage 865 39 link arm 867 39actuator torque ring 869 39 pneumatic operator 871 39 Engaged andDisengaged Positions 40 arrow A 41 workpiece standoff 865 41 bend 866 42Finger Assembly Seal 42 868 42 rim portion 870 42 Methods and Operation44

[0031] Workpiece Support

[0032] Turning now to FIG. 1, a semiconductor processing machine 400having two workpiece supports 401 is shown. Workpiece support 402 isshown in a “open” or “receive wafer” position in order to receive aworkpiece or semiconductor wafer for further processing. Workpiecesupport 403 is shown in a “closed” or “deployed” position wherein thesemiconductor wafer has been received by the workpiece support and isbeing exposed to the semiconductor manufacturing process in thesemiconductor manufacturing chamber 404. FIG. 1 also shows an optionalbeam emitter 81 for emitting a laser beam detected by robotic waferconveyors to indicate position of the unit.

[0033] Turning now to FIG. 2, an enlarged view of the workpiece support401 is shown. Workpiece support 401 advantageously includes operatorbase 405, a processing head 406, and an operator arm 407. Processinghead 406 preferably includes workpiece holder or wafer holder 408 andwhich further includes fingers 409 for securely holding the workpieceduring further process and manufacturing steps. Workpiece holder 408more preferably spins about workpiece spin axis 410.

[0034] The processing head is advantageously rotatable about processinghead pivot axis or, more briefly termed, process pivot axis 411. In thismanner, a workpiece (not shown) may be disposed between and grasped bythe fingers 409, at which point the processing head is preferablyrotated about process head pivot axis 411 to place the workpiece in aposition to be exposed to the manufacturing process.

[0035] In the preferred embodiment, operator arm 407 may be pivotedabout operator pivot axis 412. In this manner, the workpiece isadvantageously lowered into the process bowl (not shown) to accomplish astep in the manufacture of the semiconductor wafer.

[0036] Turning now to FIGS. 3-5, the sequence of placing a workpiece onthe workpiece support and exposing the workpiece to the semiconductormanufacturing process is shown. In FIG. 3, a workpiece W is shown asbeing held in place by fingertips 414 of fingers 409. Workpiece W isgrasped by fingertips 414 after being placed in position by robot orother means.

[0037] Once the workpiece W has been securely engaged by fingertips 414,processing head 406 can be rotated about process head pivot axis 411 asshown in FIG. 4. Process head 406 is preferably rotated about axis 411until workpiece W is at a desired angle, such as approximatelyhorizontal. The operator arm 407 is pivoted about operator arm pivotaxis 412 in a manner so as to coordinate the angular position ofprocessing head 406. In the closed position, the processing head isplaced against the rim of bowl 416 and the workpiece W is essentially ina horizontal plane. Once the workpiece W has been secured in thisposition, any of a series of various semiconductor manufacturing processsteps may be applied to the workpiece as it is exposed in the processingbowl 417.

[0038] Since the processing head 406 is engaged by the operator arm 407on the left and right side by the preferably horizontal axis 411connecting the pivot points of processing head 406, a high degree ofstability about the horizontal plane is obtained. Further, since theoperator arm 407 is likewise connected to the operator base 405 at leftand right sides along the essentially horizontal line 412 connecting thepivot points of the operator arm, the workpiece support forms astructure having high rigidity in the horizontal plane parallel to anddefined by axes 411 and 412. Finally, since operator base 405 issecurely attached to the semiconductor process machine 400, rigidityabout the spin axis 410 is also achieved.

[0039] Similarly, since processing head 406 is nested within the fork oryoke shaped operator arm 407 having left and right forks 418 and 419,respectively, as shown in FIG. 2, motion due to cantilevering of theprocessing head is reduced as a result of the reduced moment arm definedby the line connecting pivot axes 411 and 412.

[0040] In a typical semiconductor manufacturing process, the workpieceholder 408 will rotate the workpiece, having the process head 406secured at two points, that is, at the left and right forks 418 and 419,respectively, the vibration induced by the rotation of the workpieceholder 408 will be significantly reduced along the axis 411.

[0041] A more complete description of the components of the presentinvention and their operation and interrelation follows.

Operator Base

[0042] Turning now to FIG. 9, operator base 405 is shown. The presentinvention advantageously includes an operator base 405 which forms anessentially yoke-shaped base having an operator base back portion 420,an operator base left yoke arm 421, and an operator base right, yoke arm422. Yoke arms 421 and 422 are securely connected to the base of theyoke 420. In the preferred embodiment, the yoke arms are secured to theyoke base by the yoke arm fasteners 423. The yoke arm base in turn isadvantageously connected to the semiconductor process machine 400 asshown in FIG. 1.

[0043] The upper portions of the yoke arm advantageously includereceptacles for housing the operator arm bearings 424 which are used tosupport the pivot shafts of the operator arm 425, described more fullybelow.

Operator Arm

[0044] Still viewing. FIG. 9, the present invention advantageouslyincludes an operator arm 407. As described previously, operator arm 407preferably pivots about the operator arm pivot axis 412 which connectsthe center line defined by the centers of operator arm pivot bearings424.

[0045] Operator arm or pivot arm 407 is advantageously constructed insuch a manner to reduce mass cantilevered about operator arm pivot axis412. This allows for quicker and more accurate positioning of the pivotarm as it is moved about pivot arm axis 412.

[0046] The left fork of the pivot arm 418, shown moreclearly in FIG. 11,houses the mechanism for causing the pivot arm to lift or rotate aboutpivot arm pivot axis 412. Pivot arm right fork 419, shown more clearlyin FIG. 10, houses the mechanism for causing the processing head 406(not shown) to rotate about the process head pivot axis 411.

[0047] The process arm rear cavity 426, shown in FIG. 9, houses the liftmotor 452 for causing the operator arm 407 to rotate about pivot armaxis 412. Process arm rear cavity 426 also houses rotate motor 428 whichis used to cause the processing head 406 to rotate about the processinghead pivot axis 411. The rotate motor 428 may more generally bedescribed as a processing head pivot or rotate drive. Processing head406 is mounted to operator arm 407 at processing head left pivot shaft429 and processing head right pivot shaft 430.

[0048] Operator arm 407 is securely attached to left yoke arm 421 andright yoke arm 422 by operator arm pivot shafts 425 and operator armpivot bearings 424, the right of which such bearing shaft and bearingsare shown in FIG. 9.

Operator Arm-Processing Head Rotate Mechanism

[0049] Turning now to FIG. 13, a sectional plan view of the right rearcorner of operator arm 407 is shown. The right rear section of operatorarm 407 advantageously contains the rotate mechanism which is used torotate processing head 406 about processing head pivot shafts 430 and429. Processing head rotate mechanism 431 preferably consists of rotatemotor 428 which drives rotate shaft 432, more generally described as aprocessing head drive shaft. Rotate shaft 432 is inserted within rotatepulley 425 which also functions as the operator arm pivot shaft. Asdescribed previously, the operator arm pivot shaft/lift pulley issupported in operator arm pivot bearings 424, which are themselvessupported in operator base yoke arm 422. Rotate shaft 432 is securedwithin left pulley 424 by securing collar 433. Securing collar 433secures rotate pulley 425 to rotate shaft 432 in a secure manner so asto assure a positive connection between rotate motor 428 and rotatepulley 425. An inner cover 584 is also provided.

[0050] Rotate motor 428 is disposed within process arm rear cavity 426and is supported by rotate motor support 434. Rotate motor 428preferably is a servo allowing for accurate control of speed andacceleration of the motor. Servo motor 428 is advantageously connectedto rotate encoder 435 which is positioned on one end of rotate motor428. Rotate encoder 435, more generally described as a processing headencoder, allows for accurate measurement of the number of rotations ofrotate motor 428, as well as the position, speed, and acceleration ofthe rotate shaft 432. The information from the rotate encoder may beused in a rotate circuit which may then be used to control the rotatemotor when the rotate motor is a servo. This information is useful inobtaining the position and rate of travel of the processing head, aswell as controlling the final end point positions of the processing headas it is rotated about process head rotate axis 411.

[0051] The relationship between the rotate motor rotations, as measuredby rotate encoder 435, may easily be determined once the diameters ofthe rotate pulley 425 and the processing head pulley 438 are known.These diameters can be used to determine the ratio of rotate motorrelations to processing head rotations. This may be accomplished by amicroprocessor, as well as other means.

[0052] Rotate pulley 425 is further supported within operator arm 407 byrotate pulley inboard bearing 436 which is disposed about an extendedflange on the rotate pulley 425. Rotate pulley inboard bearing 436 issecured by the body of the operator arm 407, as shown in FIG. 13.

[0053] Rotate pulley 425 advantageously drives rotate belt 437, moregenerally described as a flexible power transmission coupling. Referringnow to FIG. 10, rotate belt 437 is shown in the side view of the rightarm 419 of the operator arm 407. Rotate belt 437 is preferably a toothedtiming belt to ensure positive engagement with the processing head drivewheel, more particularly described herein as the processing head pulley438, (not shown in this view). In order to accommodate the toothedtiming belt 437, both the rotate pulley 425 and the processing headpulley 438 are advantageously provided with gear teeth to match thetooth pattern of the timing belt to assure positive engagement of thepulleys with the rotate belt.

[0054] Rotate mechanism 431 is preferably provided with rotate belttensioner 439, useful for adjusting the belt to take up slack as thebelt may stretch during use, and to allow for adjustment of the belt toassure positive engagement with both the rotate pulley and theprocessing head pulley. Rotate belt tensioner 439 adjusts the tension ofrotate belt 437 by increasing the length of the belt path between rotatepulley 425 and processing head pulley 438, thereby accommodating anyexcess length in the belt. Inversely, the length of the belt path mayalso be shortened by adjusting rotate belt tensioner 439 so as to createa more linear path in the upper portion of rotate belt 437. Thetensioner 439 is adjusted by rotating it about tensioner hub 468 andsecuring it in a new position.

[0055] Turning now to FIG. 13, processing head pulley 438 is mounted toprocessing head rotate shaft 430 in a secured manner so that rotation ofprocessing head pulley 438 will cause processing head rotate shaft 430to rotate. Processing head shaft 430 is mounted to operator arm rightfork 419 by processing head shaft bearing 440, which in turn is securedin the frame of the right fork 419 by processing head rotate bearing469. In a like manner, processing head shaft 429 is mounted in operatorarm left fork 418 by processing head shaft bearing 441, as shown in FIG.9.

[0056] Processing head pivot shafts 430 and 429 are advantageouslyhollow shafts. This feature is useful in allowing electrical optical,pneumatic, and other signal and supply services to be provided to theprocessing head. Service lines such as those just described which arerouted through the hollow portions of processing head pivot shafts 429and 430 are held in place in the operator arms by cable brackets 442 and443. Cable brackets 442 and 443 serve a dual purpose. First, routing theservice lines away from operating components within the operator armleft and right forks. Second, cable brackets 442 and 443 serve a usefulfunction in isolating forces imparted to the service cables by therotating action of processing head 406 as it rotates about processinghead pivot shafts 429 and 430. This rotating of the processing head 406has the consequence that the service cables are twisted within the pivotshafts as a result of the rotation, thereby imparting forces to thecables. These forces are preferably isolated to a particular area so asto minimize the effects of the forces on the cables. The cable brackets442 and 443 achieve this isolating effect.

[0057] The process head rotate mechanism 431, shown in FIG. 13, is alsoadvantageously provided with a rotate overtravel protect 444,whichfunctions as a rotate switch. Rotate overtravel protect 444 preferablyacts as a secondary system to the rotate encoder 435 should the controlsystem fail for some reason to stop servo 428 in accordance with apredetermined position, as would be established by rotate encoder 435.Turning to FIG. 13, the rotate overtravel protect 444 is shown in planview. The rotate overtravel protect preferably consists of rotateoptical switches 445 and 446, which are configured to correspond to theextreme (beginning and end point) portions of the processing head, aswell as the primary switch component which preferably is a rotate flag447. Rotate flag 447 is securely attached to processing head pulley 438such that when processing head shaft 430 (and consequently processinghead 406) are rotated by virtue of drive forces imparted to theprocessing head pulled 425 by the rotate belt 437, the rotate flag 447will rotate thereby tracking the rotate motion of processing head 406.Rotate optical switches 445 and 446 are positioned such that rotate flag447 may pass within the optical path generated by each optical switch,thereby generating a switch signal. The switch signal is used to controlan event such as stopping rotate motor 428. Rotate optical switch 445will guard against overtravel of processing head 406 in one direction,while rotate optical switch 446 will provide against overtravel of theprocessing head 406 in the opposite direction.

Operator Arm-Lift Mechanism

[0058] Operator arm 407 is also advantageously provided with an operatorarm lift mechanism 448 which is useful for causing the operator arm tolift, that is, to pivot or rotate about operator arm pivot axis 412.Turning to FIG. 14, the operator arm lift mechanism 448 is shown in thesectional plan view of the right rear corner of operator arm 407.

[0059] Operator arm lift mechanism 448 is advantageously driven by liftmotor 452. Lift motor 452 may be more generally described as an operatorarm drive or operator arm pivot drive. Lift motor 452 is preferably aservo motor and is more preferably provided with an operator encoder,more specifically described as lift motor encoder 456. When lift motor452 is a servo motor coupled with lift encoder 456, informationregarding the speed and absolute rotational position of the lift motorshaft 454 may be known from the lift encoder signal. Additionally, byvirtue of being a servo mechanism, the angular speed and acceleration oflift motor 452 may be easily controlled by use of the lift signal by anelectrical circuit. Such a lift circuit may be configured to generatedesired lift characteristics (speed, angle, acceleration, etc.). FIG. 14shows that the lift operator may also include a brake 455 which is usedto safely stop the arm if power fails.

[0060] Lift motor 452 drives lift motor shaft 454 which in turn driveslift gear drive 453. Lift gear drive 453 is a gear reduction drive toproduce a reduced number of revolutions at lift drive shaft 456 as thefunction of input revolutions from lift motor shaft 454.

[0061] Lift drive gear shaft 456 is secured to lift anchor 451 which ismore clearly shown in FIG. 11. Lift anchor 451 is preferably shaped tohave at least one flat side for positively engaging lift bushing 449.Lift anchor 451 is secured to lift drive shaft 456 by anchor plate 458and anchor fasteners 457. In this manner, when lift drive shaft 456 isrotated, it will positively engage lift bushing 449. Returning to FIG.14, it is seen that lift bushing 449 is mounted in operator left yokearm 421, and is thus fixed with respect to operator base 405. Liftbearing 450 is disposed about the lift bushing shank and is supported inoperator arm 407 by lift bearing support 460 which is a bushingconfigured to receive lift bearing 450 on a first end and to supportlift gear drive 453 on a second end. Lift bearing support 460 is furthersupported within operator arm 407 by operator arm frame 461. The liftarm is thus free to pivot about lift bushing 449 by virtue of liftbearing 450.

[0062] In operation, as lift motor 452 causes lift gear drive 453 toproduce rotations at gear drive shaft 456, lift anchor 451 is forcedagainst lift bushing 449 which is securely positioned within rightoperator yoke arm 421. The reactive force against the lift anchor 451will cause lift bearing support 460 to rotate relative to lift bushing449. Since lift bushing 449 is fixed in operator base 405, and sinceoperator base 405 is fixed to processing machine 400, rotation of liftbearing support 460 will cause lift arm 407 to pivot about operator armpivot axis 412, thereby moving the processing head 406. It isadvantageous to consider the gear drive shaft (or “operator arm shaft”)as being fixed with respect to operator base 405 when envisioning theoperation of the lift mechanism.

[0063] Operator lift mechanism 448 is also advantageously provided witha lift overtravel protect 462 or lift switch. The, lift rotate protectoperates in a manner similar to that described for the rotate overtravelprotect 444 described above. Turning now to FIG. 11, a left side view ofthe operator arm 407 is shown which shows the lift overtravel protect indetail.

[0064] The lift overtravel protect preferably includes a lift opticalswitch low 463 and a lift optical switch high 464. Other types of limitswitches can also be used. The switch high 464 and switch low 463correspond to beginning and endpoint travel of lift arm 407. The primarylift switch component is lift flag 465, which is firmly attached to leftoperator base yoke arm 421. The lift optical switches are preferablymounted to the movable operator arm 407. As operator arm 407 travels inan upward direction in pivoting about operator arm pivot axis 412, liftoptical switch high 464 will approach the lift flag 465. Should the liftmotor encoder 455 fail to stop the lift motor 454, as desired, the liftflag 465 will break the optical path of the lift optical switch high 464thus producing a signal which can be used to stop the lift motor. Inlike manner, when the operator arm 407 is being lowered by rotating itin a clockwise direction about the operator arm pivot axis 412, as shownin FIG. 11, overtravel of operator arm 407 will cause lift opticalswitch low 463 to have its optical path interrupted by lift flag 465,thus producing a signal which may be used to stop lift motor 452. As isshown in FIG. 11, lift flag 465 is mounted to left operator base yokearm 421 with slotted lift flag mounting slots 467 and removable liftflag fasteners 466. Such an arrangement allows for the lift flag to beadjusted so that the lift overtravel protect system only becomes activeafter the lift arm 407 has traveled beyond a preferred point.

Processing Head

[0065] Turning now to FIG. 6, a front elevation schematic view of theprocessing head 406 is shown. Processing head 406 is described in moredetail in FIGS. 7 and 8. Turning now to FIG. 7, a sectional view of theleft front side of processing head 406 is shown. Processing head 406advantageously includes a processing head housing 470 and frame 582.Processing head 406 is preferably round in shape in plan view allowingit to easily pivot about process head pivot axis 411 with nointerference from operator arm 407, as demonstrated in FIGS. 3-5.Returning to FIG. 7, processing head housing 470 more preferably hascircumferential grooves 471 which are formed into the side of processhead housing 470. Circumferential grooves 471 have a functional benefitof increasing heat dissipation from processing head 406.

[0066] The sides of processing head housing 470 are advantageouslyprovided with rotate shaft openings 474 and 475 for receivingrespectively left and right processing head pivot shafts 429 and 430.Processing head pivot shafts 429 and 430 are secured to the processinghead 406 by respective left and right processing head mounts 472 and473. Processing head mounts 472 and 473 are affirmative connected toprocessing head frame 582 which also supports processing head door 476which is itself securely fastened to processing head housing 470.Consequently, processing head pivot shafts 429 and 430 are fixed withrespect to processing head 407 and may therefore rotate or pivot withrespect to operator arm 407. The details of how processing head pivotshafts 429 and 430 are received within operator arm 407 were discussedsupra.

[0067] Processing head housing 470 forms a processing head void 477which is used to house additional processing head components such as sthe spin motor, the pneumatic finger actuators, and service lines, alldiscussed more fully below.

[0068] The processing head also advantageously includes a workpieceholder and fingers for holding a workpiece, as is also more fullydescribed below.

Processing Head Spin Motor

[0069] In a large number of semiconductor manufacturing processes, isdesirable to spin the semiconductor wafer or workpiece during theprocess, for example to assure even distribution of applied processfluids across the face of the semiconductor wafer, or to aid drying ofthe wafer after a wet chemistry process. It is therefore desirable to beable to rotate the semiconductor workpiece while it is held by theprocessing head.

[0070] The semiconductor workpiece is held during the process byworkpiece holder 478 described more fully below. In order to spinworkpiece holder 478 relative to processing head 406 about spin axis479, an electric, pneumatic, or other type of spin motor or workpiecespin drive is advantageously provided.

[0071] Turning to FIG. 8, spin motor 480 has armatures 526 which drivespin motor shaft 483 in rotational movement to spin workpiece holder478. Spin motor 480 is supported by bottom motor bearing 492 in bottommotor housing 482. Bottom motor housing 482 is secured to processinghead 406 by door 476. Spin motor 480 is thus free to rotate relative toprocessing head housing 470 and door 476. Spin motor 480 is preferablyadditionally held in place by top motor housing 481 which rests onprocessing head door 476. Spin motor 480 is rotationally isolated fromtop motor housing 481 by top motor bearing 493, which is disposedbetween the spin motor shaft 483 and top motor housing 481.

[0072] The spin motor is preferably an electric motor which is providedwith an electrical supply source through pivot shaft 429 and/or 430.Spin motor 480 will drive spin motor shaft 483 about spin axis 479.

[0073] To secure workpiece holder rotor 484 to spin motor shaft 483,workpiece holder, rotor 484 is preferably provided with a rotor hub 485.Rotor hub 485 defines a rotor hub recess 486 which receives a flared endof workpiece holder shaft 491. The flared end 487 of workpiece holdershaft 491 is secured within the rotor hub recess 486 by workpiece shaftsnap-rings 488 which fits within rotor recess groove 489 above theflared portion 487 of workpiece holder shaft 491.

[0074] The workpiece holder shaft 491 is fitted inside of spin motorshaft 483 and protrudes from the top of the spin motor shaft. The top ofworkpiece holder shaft 491 is threaded to receive thin nut 527 (see FIG.7). Thin nut 527 is tightened against optical tachometer 499 (describemore fully below). Optical tachometer 499 is securely attached to spinmotor shaft 483 such that as the spin motor 480 rotationally drives thespin motor shaft 483, the workpiece holder shaft 491 is also driven.

[0075] Workpiece holders may be easily changed out to accommodatevarious configurations which may be required for the various processesencountered in manufacturing of the semiconductors. This is accomplishedby removing spin encoder 498 (described below), and then thin nut 527.Once the thin nut has been removed the workpiece holder 478 will dropaway from the processing head 406.

[0076] The processing head is also advantageously provided with a spinencoder 498, more generally described as a workpiece holder encoder, andan optical tachometer 499. As shown in FIG. 7, spin encoder 498 ismounted to top motor housing 481 by encoder support 528 so, as to remainstationary with respect to the processing head 406. Optical tachometer499 is mounted on spin motor shaft 483 so as to rotate with the motor480. When operated in conjunction, the siring encoder 498 and opticaltachometer 499 allow the speed, acceleration, and precise rotationalposition of the spin motor shaft (and therefore the workpiece holder478) to be known. In this manner, and when spin motor 480 is provided asa servo motor, a high degree of control over the spin rate,acceleration, and rotational angular position of the workpiece withrespect to the process head 407 may be obtained.

[0077] In one application of the present invention the workpiece supportis used to support a semiconductor workpiece in an electroplatingprocess. To accomplish the electroplating an electric current isprovided to the workpiece through an alternate embodiment of the fingers(described more fully below). To provide electric current to the finger,conductive wires are run from the tops of the fingers inside of theworkpiece holder 478 through the electrode wire holes 525 in the flareda lower part of workpiece holder shaft 491. The electrode wires areprovided electric current from electrical lines run through processingpivot shaft 429 and/or 430.

[0078] The electrical line run through pivot shaft 430/429 will bynature be stationary with respect to processing head housing 470.However, since the workpiece holder rotor is intended to be capable ofrotation during the electroplating process, the wires passing intoworkpiece support shaft 491 through electrode wire holes 525 may rotatewith respect to processing head housing 470. Since the rotatingelectrode wires within workpiece shaft 491 and the stationary electricalsupply lines run through pivot shaft 430/429 must be in electricalcommunication, the rotational/stationary problem must be overcome. Inthe preferred embodiment, this is accomplished by use of electrical slipring 494.

[0079] Electrical slip ring 494, shown in FIG. 7, has a lower wirejunction 529 for receiving the conductive ends of the electrical wirespassing into workpiece holder shaft 491 by electrode wire holes 525.Lower wire junction 529 is held in place within workpiece holder shaft491 by insulating cylindrical collar 497 and thus rotates with spinmotor shaft 483. The electrode wires terminate in a single electricalcontact 531 at the top of the lower wire junction 529. Electrical slipring 494 further has a contact pad 530 which is suspended within the topof workpiece holder shaft 491. Contact pad 530 is mechanically fastenedto spin encoder 498, which, as described previously, remains stationarywith respect to processing head housing 470. Thestationary-to-rotational transition is made at the tip of contact pad530, which is in contact with the rotating electrical contact 531.Contact pad 530 is electrically conductive and is in electricalcommunication with electrical contact 531. In the preferred embodiment,contact pad 530 is made of copper-beryllium. A wire 585 carries currentto finger assemblies when current supply is needed, such as on thealternative embodiment described below.

Processing Head Finger Actuators

[0080] Workpiece holder 478, described more fully below, advantageouslyincludes fingers for holding the workpiece W in the workpiece holder, asshown in FIGS. 7 and 8. Since the workpiece holder 478 may be removed asdescribed above, it is possible to replace one style of workpiece holderwith another. Since a variety of workpiece holders with a variety offingers for holding the workpiece is possible, it is desirable to have afinger actuator mechanism disposed within processing head 407 which iscompatible with any given finger arrangement. The invention is thereforeadvantageously provided with a finger actuator mechanism.

[0081] Turning to FIG. 7, a finger actuator mechanism 500 is shown.Finger actuator mechanism 500 is preferably a pneumatically operatedmechanism. A pneumatic cylinder is formed by a cavity 501 within topmotor housing 481. Pneumatic piston 502 is disposed within cavity 501.Pneumatic piston 502 is biased in an upward position within cavity 501by actuator spring 505. Actuator spring 505 is confined within cavity501 by cavity end cap 507, which is itself constrained by retaining ring508. Pneumatic fluid is provided to the top of pneumatic piston 502 viapneumatic inlet 503. Pneumatic fluid is provided to pneumatic inlet 503by pneumatic supply line 504 which is routed through processing headpivot shaft 429 and hence through the left fork 418 of the operator arm407. Turning to FIG. 8, it can be seen that a second pneumatic cylinderwhich is identical to the pneumatic cylinder just described is alsoprovided.

[0082] Pneumatic piston 502 is attached to actuator plate 509 byactuator plate connect screw 510. Wave springs 529 provide flexibilityto the connecting at screws 510. Actuator plate 509 is preferably anannular plate concentric with the spin motor 580 and disposed about thebottom motor housing 482, and is symmetrical about spin axis 479.Actuator plate 509 is secured against pneumatic piston 502 by bushing512 which is disposed in pneumatic piston recess 511 about pneumaticpiston 502. Bushing 512 acts as a support for wave springs 529 to allowa slight tilting of the actuator plate 509. Such an arrangement isbeneficial for providing equal action against the finger actuatorcontracts 513 about the entire actuator plate or ring 509.

[0083] When pneumatic fluid is provided to the space above the pneumaticpiston 502, the pneumatic piston 502 travels in a downward directioncompressing actuator spring 505. As pneumatic piston 502 travelsdownward, actuator plate 509 is likewise pushed downward by flexiblebushing 512. Actuator plate 509 will contact finger actuator contacts513 causing the fingers to operate as more fully described below.

[0084] Actuator seals 506 are provided to prevent pneumatic gas frombypassing the top of the pneumatic piston 502 and entering the areaoccupied by actuator spring 505.

Processing Head Workpiece Holder

[0085] Workpiece holder 478 is used to hold the workpiece W, which istypically a semiconductor wafer, in position during the semiconductormanufacturing process.

[0086] Turning now to FIG. 8, a finger 409 is shown in cross section.Finger 409 advantageously includes a finger actuator contact 513 whichis contacted by actuator plate 509, as described above. Finger actuatorcontact 513 is connected to finger actuator lever 514 (more generally,“finger extensions”) which is cantilevered from and connected to thefinger stem 515. Finger stem 515 is inserted into finger actuator lever514. Disposed about the portion of the finger actuator lever whichencompasses and secures finger stem 515 is finger diaphragm 519. Fingerdiaphragm 519 is preferably made of a flexible material such asTetrafluoroethylene, also known as Teflon® (registered trademark of E.I. DuPont de Nemours Company). Finger 409 is mounted to workpiece holderrotor 484 using finger diaphragm 519. Finger diaphragm 519 is insertedinto the finger opening 521 in rotor 484. The finger diaphragm 519 isinserted into the rotor from the side opposite that to which theworkpiece will be presented. Finger diaphragm 519 is secured to rotor484 against rotor diaphragm lip 523. Forces are intentionally impartedas a result of contact between the actuator plate 509 and the fingeractuator contact 513 when the finger actuator mechanism 500 is actuated.

[0087] Finger actuator lever 514 is advantageously biased in ahorizontal position by finger spring 520 which acts on finger actuatortab 522 which in turn is connected to finger actuator lever 514. Fingerspring 520 is preferably a torsion spring secured to the workpieceholder rotor 484.

[0088] Finger stem 515 is also preferably provided with finger collar ornut 517 which holds the finger stem 515 against shoulder 518. Fingercollar 517 threads or otherwise securely fits over the lower end offinger actuator lever 514. Below the finger collar 517, finger stem 515extends for a short distance and terminates in fingertip 414. Fingertip414 contains a slight groove or notch which is beneficially shaped toreceive the edge of the workpiece W.

[0089] In actuation, finger actuator plate 509 is pushed downward byfinger actuator mechanism 500. Finger actuator plate 509 continues itsdownward travel contacting finger actuator contacts 513. As actuatorplate 509 continues its downward travel, finger actuator contacts arepushed in a downward direction. As a result of the downward direction,the finger actuator levers 514 are caused to pivot.

[0090] In the preferred embodiment, a plurality of fingers are used tohold the workpiece. In one example, six fingers were used. Once theactuator plate 509 has traveled its full extent, the finger stems 515will be tilted away from the spin axis 479. The circumference describedby the fingertips in this spread-apart position should be greater thanthe circumference of the workpiece W. Once a workpiece W has been ispositioned proximate to the fingertips, the pneumatic pressure isrelieved on the finger actuator and the actuator spring 505 causes thepneumatic piston 502 to return to the top of the cavity 501. In sodoing, the actuator plate 509 is retracted and the finger actuatorlevers are returned to their initial position by virtue of fingersprings 520.

Semiconductor Workpiece Holder—Electroplating Embodiment

[0091]FIG. 15 is a side elevational view of a semiconductor workpieceholder 810 constructed according to a preferred aspect of the invention.

[0092] Workpiece holder 810 is used for processing a semiconductorworkpiece such as a semiconductor wafer shown in phantom at W. Onepreferred type of processing undertaken with workpiece holder 810 is aworkpiece electroplating process in which a semiconductor workpiece isheld by workpiece holder 810 and an electrical potential is applied tothe workpiece to enable plating material to be plated thereon. Such canbe, and preferably is accomplished utilizing a processing enclosure orchamber which includes a bottom half or bowl 811 shown in phantom linesin FIG. 1. Bottom half 811 together with workpiece holder 810 forms asealed, protected chamber for semiconductor workpiece processing.Accordingly, preferred reactants can be introduced into the chamber forfurther processing. Another preferred aspect of workpiece holder 810 isthat such moves, rotates or otherwise spins the held workpiece duringprocessing as will be described in more detail below.

Processing Head and Processing Head Operator

[0093] Turning now to FIG. 15, semiconductor workpiece holder 810includes a workpiece support 812. Workpiece support 812 advantageouslysupports a workpiece during processing. Workpiece support 812 includes aprocessing head or spin head assembly 814. Workpiece support 812 alsoincludes a head operator or lift/rotate assembly 816. Spin head assembly814 is operatively coupled with lift/rotate assembly 816. Spin headassembly 814 advantageously enables a held workpiece to be spun or movedabout a defined axis during processing. Such enhances conformal coverageof the preferred plating material over the held workpiece. Lift/rotateassembly 816 advantageously lifts spin head assembly 814 out ofengagement with the bottom half 811 of the enclosure in which thepreferred processing takes place. Such lifting is preferably about anaxis x₁. Once so lifted, lift/rotate assembly 816 also rotates the spinhead and held workpiece about an axis x₂ so that the workpiece can bepresented face-up and easily removed from workpiece support 812. In theillustrated and preferred embodiment, such rotation is about 180° fromthe disposition shown in FIG. 15. Advantageously, a new workpiece can befixed or otherwise attached to the workpiece holder for furtherprocessing as described in detail below.

[0094] The workpiece can be removed from or fixed to workpiece holder810 automatically by means of a robotically controlled arm.Alternatively, the workpiece can be manually removed from or fixed toworkpiece holder 810. Additionally, more than one workpiece holder canbe provided to support processing of multiple semiconductor workpieces.Other means of removing and fixing a semiconductor workpiece arepossible.

[0095]FIG. 16 is a front sectional view of the FIG. 15 semiconductorworkpiece holder. As shown, workpiece support 812 includes a motor 818which is operatively coupled with a rotor 820. Rotor 820 isadvantageously mounted for rotation about a rotor spin axis 822 andserves as a staging platform upon which at least one finger assembly 824is mounted. Preferably, more than one finger assembly is mounted onrotor 820, and even more preferably, four or more such finger assembliesare mounted thereon and described in detail below although only two areshown in FIG. 16. The preferred finger assemblies are instrumental infixing or otherwise holding a semiconductor workpiece on semiconductorworkpiece holder 810. Each finger assembly is advantageously operativelyconnected or associated with a actuator 825. The actuator is preferablya pneumatic linkage which serves to assist in moving the fingerassemblies between a disengaged position in which a workpiece may beremoved from or added to the workpiece holding, and an engaged positionin which the workpiece is fixed upon the workpiece holder forprocessing. Such is described in more detail below.

[0096]FIG. 17 is a top or plan view of rotor 820 which is effectivelytaken along line 3-3 in FIG. 16. FIG. 16 shows the preferred .fourfinger assemblies 824. As shown, rotor 820 is generally circular andresembles from the top a spoked wheel with a nearly continuous bottomsurface. Rotor 820 includes a rotor center piece 826 at the center ofwhich lies rotor axis 822. A plurality of struts or spokes 828 arejoined or connected to rotor center 826 and extend outwardly to joinwith and support a rotor perimeter piece 830. Advantageously, four ofspokes 828 support respective preferred finger assemblies 824. Fingerassemblies 824 are advantageously positioned to engage a semiconductorworkpiece, such as a wafer W which is shown in phantom lines in theposition such would occupy during processing. When a workpiece is soengaged, it is fixedly held in place relative to the rotor so thatprocessing can be effected. Such processing can include exposing theworkpiece to processing conditions which are effective to form a layerof material on one or more surfaces or potions of a wafer or otherworkpiece. Such processing can also include moving the workpiece withina processing-environment to enhance or improve conformal coverage of alayering material. Such processing can, and preferably does includeexposing the workpiece to processing conditions which are effective toform an electroplated layer on or over the workpiece.

Finger Assembly

[0097] Referring now to FIGS. 18-20, various views of a preferred fingerassembly are shown. The preferred individual finger assemblies areconstructed in accordance with the description below. FIG. 18 is anisolated side sectional view of a finger assembly constructed inaccordance with a preferred aspect of the invention. FIG. 19 is a sideelevational view of the finger assembly turned 90° from the, view ofFIG. 18. FIG. 20 is a fragmentary cross-sectional enlarged view of afinger assembly and associated rotor structure. The finger assembly asset forth in FIGS. 18 and 19 is shown in the relative position such asit would occupy when processing head or spin head assembly 814 (FIGS. 15and 16) is moved or rotated by head operator or lift/rotate assembly 816into a position for receiving a semiconductor workpiece. The fingerassembly is shown in FIGS. 18 and 20 in an orientation of about 180°from the position shown in FIG. 20. This typically varies because spinhead assembly 814 is rotated 180° from the position shown in FIGS. 15and 16 in order to receive a semiconductor workpiece. Accordingly,finger assemblies 824 would be so rotated. Lesser degrees of rotationare possible.

[0098] Finger assembly 824 includes a finger assembly frame 832.Preferably, finger assembly frame 832 is provided in the form of asealed contact sleeve which includes an angled slot 832 a, only aportion of which is shown in FIG. 19. Angled slot 832 a advantageouslyenables the finger assembly to be moved, preferably pneumatically, bothlongitudinally and rotationally as will be explained below. Suchpreferred movement enables a semiconductor workpiece to be engaged,electrically contacted, and processed in accordance with the invention.

[0099] Finger assembly frame 832 includes a finger assembly frame outerflange 834 which, as shown in FIG. 20, engages an inner drive plateportion 836 of rotor 820. Such engagement advantageously fixes or seatsfinger assembly frame 832 relative to rotor 820. Such, in turn, enablesthe finger assembly, or a portion thereof, to be moved relative to therotor for engaging the semiconductor workpiece.

Finger Assembly Drive System

[0100] Referring to FIGS. 16 and 18-20, the finger assembly includes afinger assembly drive system which is utilized to move the fingerassembly between engaged and disengaged positions. The finger assemblydrive system includes a bearing 838 and a collet 840 operativelyadjacent the bearing. Bearing 838 includes a bearing receptacle 839 forreceiving a pneumatically driven source, a fragmented portion of whichis shown directly above the receptacle in FIG. 20. The pneumaticallydriven source serves to longitudinally reciprocate and rotate collet840, and hence a preferred portion of finger assembly 824. A preferredpneumatically driven source is described below in more detail inconnection with the preferred longitudinal and rotational movementeffectuated thereby. Such longitudinal reciprocation is affected by abiasing mechanism in the form of a spring 842 which is operativelymounted between finger assembly frame 832 and a spring seat 844. Theconstruction develop a bias between finger assembly frame 832 and springseat 844 to bias the finger into engagement against a wafer.Advantageously, the cooperation between the above mentionedpneumatically driven source as affected by the biasing mechanism of thefinger assembly drive system, enable collet 840 to be longitudinallyreciprocated in both extending and retracting modes of movement. Assuch, finger assembly 824 includes a biased portion which is biasedtoward a first position and which is movable to a second position awayfrom the first position. Other manners of longitudinally reciprocatingthe finger assembly are possible.

Finger Assembly Electrical System

[0101] Referring to FIGS. 16 and 19, the finger assembly preferablyincludes a finger assembly electrical system which is utilized toeffectuate an electrical bias to a held workpiece and supply electricalcurrent relative thereto. The finger assembly electrical system includesa pin connector 846 and a finger 848. Pin connector 84 advantageouslyprovides an electrical connection to a power source (not shown) via wire585 and associate slip ring mechanism, described above in connectionwith FIG. 7 and other FIGS. This is for delivering an

[0102] electrical bias and current to an electrode which is describedbelow. Pin connector 846 also rides within angled slot 832 a therebymechanically defining the limits to which the finger assembly may beboth longitudinally and rotationally moved.

[0103] Finger 848 is advantageously fixed or secured to or within collet840 by a nut 850 which threadably engages a distal end portion of collet840 as shown best in FIG. 18. An anti-rotation pin 852 advantageouslysecures finger 848 within collet 840 and prevents relative rotationtherebetween. Electrical current is conducted from connector 846 throughcollet 840 to finger 860, all of which are conductive, such as fromstainless steel. The finger and collet can be coated with a suitabledielectric coating 856, such as TEFLON or others. The collet 840 andfinger member 860 are in one form of the invention made hollow andtubular to conduct a purge gas therethrough.

[0104] Finger assembly 824 may also optionally include a distal tip orfinger tip 854. Tip 854 may also have a purge gas passage formedtherethrough. Finger tip 854 advantageously engages against asemiconductor workpiece (see FIG. 20) and assists in holding or fixingthe position of the workpiece relative to workpiece holder 810. Fingertip 854 also assists in providing an operative electrical connectionbetween the finger assembly and a workpiece to which an electricalbiased is to be applied and through which current can move. Finger tip85 can include an electrode contact 858 for electrically contacting asurface of a semiconductor workpiece once such workpiece is secured asdescribe below.

Finger Assembly Drive System Interface

[0105] A finger assembly drive system interface is operatively coupledwith the finger assembly drive system to effectuate movement of thefinger assembly between the engaged and disengaged positions. Apreferred finger assembly drive system interface is described withreference to FIGS. 16 and 20. One component of the finger assembly drivesystem interface is a finger actuator 862. Finger actuator 862 isadvantageously provided for moving the finger assembly between theengaged and disengaged position. Finger actuator 862 acts by engagingbearing receptacle 839 and moving finger assembly 824 between an engagedposition and a disengaged position. In the engaged position, finger tip854 is engaged against a semiconductor workpiece. In the disengagedposition finger tip 854 is moved away from the workpiece.

[0106] The finger assembly drive system interface includes pneumaticactuator 825 (FIG. 16). Pneumatic actuators 825 are operativelyconnected to an actuation ring 863 and operates thereupon causing thedrive plate to move reciprocally in the vertical direction as viewed inFIG. 16. Finger actuator 862 is operatively connected to actuation ring863 in a manner which, upon pneumatic actuation, moves the fingeractuator into engagement with bearing receptacle 839 along the dashedline in FIG. 20. Such allows or enables the finger assembly to be movedlongitudinally along a first movement path axis 864.

[0107] Pneumatic actuator linkage 825 also includes a secondary linkage865. Secondary linkage 865 is pneumatic as well and includes a link arm867. Link arm 867 is connected or joined to an actuator torque ring 869.Preferably, torque ring 869 is concentric with rotor 820 (FIG. 17) andcircuitously links each of the finger actuators together. A pneumaticoperator 811 is advantageously linked with the secondary linkage 865 forapplying force and operating the linkage by angularly displacing torquering 869. This in turn rotates the finger assemblies into and away fromthe engaged position.

[0108] Preferably finger actuator engagement bits 862, under theinfluence of pneumatic linkage 825, moves the finger assembly, and morespecifically collet 840 and finger 848 along a first axial movement pathalong axis 864. The finger actuator engagement bits 862, then under theinfluence of pneumatic operator 871 are turned about the axes of eachbit like a screwdriver. This moves collet 840 and finger 848 in a secondangular movement. Such second movement turns the fingers sufficiently toproduce the angular displacement shown in FIG. 21. According to apreferred aspect of this invention, such movement of the fingerassemblies between the engaged and disengaged positions takes place whenspin head assembly 814 has been moved 180° from its FIG. 21 dispositioninto a face-up condition.

[0109] The engagement bits 862 can be provided with a purge gas passagetherethrough. Gas is supplied via tube 893 and is passed through thefinger assemblies.

Engaged and Disengaged Positions

[0110]FIG. 21 is a view of a portion of a finger assembly, taken alongline 7-7 in FIG. 18. Such shows in more detail the above-describedengaged and disengaged positions and movement therebetween relative to aworkpiece W. In the disengaged position, finger 848 is positionedadjacent the semiconductor workpiece and the finger tip and electrodecontact do not overlap with workpiece W. In the engaged position, thefinger tip overlaps with the workpiece and the electrode is brought tobear against the workpiece. From the disengaged position, fingerassembly 824, upon the preferred actuation, is moved in a firstdirection away from, the disengaged position. Preferably, such firstdirection is longitudinal and along first movement path axis 864. Suchlongitudinal movement is linear and in the direction of arrow A as shownin FIGS. 18 and 19. The movement moves the finger assembly to theposition shown in dashed lines in FIG. 18. Such movement is effectuatedby pneumatic operator 825 which operates upon actuation ring 863 (FIG.16). This in turn, causes finger actuator 862 to engage with fingerassembly 824. Such linear movement is limited by angled slot 832 a.Thereafter, the finger assembly is preferably moved in a second adirection which is different from the first direction and preferablyrotational about the first movement path axis 864. Such is illustratedin FIG. 21 where the second direction defines a generally actuate pathbetween the engaged and disengaged positions. Such rotational movementis effectuated by secondary linkage 865 which pneumatically engages thefinger actuator to effect rotation thereof. As so moved, the fingerassembly swings into a ready position in which a semiconductor workpieceis ready to be engaged and held for processing. Once the finger assemblyis moved or swung into place overlapping a workpiece, the preferredfinger actuator is spring biased and released to bear against theworkpiece. An engaged workpiece is shown in FIG. 20 after the workpiecehas been engaged by finger tip 854 against a workpiece standoff 865, andspin head assembly 814 has been rotated back into the position shown inFIG. 15. Such preferred pneumatically assisted engagement takes placepreferably along movement path axis 864 and in a direction which isinto, the plane of the page upon which FIG. 21 appears.

[0111] As shown in FIG. 18, finger 848 extends away from collet 840 andpreferably includes a bend 866 between collet 840 and finger tip 854.The preferred bend is a reverse bend of around 180° which serves topoint finger tip 854 toward workpiece W when the finger assembly ismoved toward or into the engaged position (FIG. 21). Advantageously, thecollet 840 and hence finger 848 are longitudinally reciprocally movableinto and out of the engaged position.

Finger Assembly Seal

[0112] The finger assembly preferably includes a finger assembly seal868 which is effectuated between finger 848 and a desired workpiece whenthe finger assembly is moved into the engaged position. Preferably,adjacent finger tip 854. Seal 868 is mounted adjacent electrode contact858 and effectively seals the electrode contact therewithin when fingerassembly 824 is moved to engage a workpiece. The seal can be made of asuitable flexible, preferably elastomeric material, such as VITON.

[0113] More specifically, and referring to FIG. 22, seal 868 can includea rim portion 870 which engages workpiece surface W and forms a sealingcontact therebetween when the finger assembly is moved to the engagedposition. Such seal advantageously isolates finger electrode 860 fromthe processing environment and materials which may plate out orotherwise be encountered therein. Seal 868 can be provided with anoptional bellows wall structure 894 (FIG. 22), that allows more axialflexibility of the seal.

[0114]FIG. 22 shows, in solid lines, seal 868 in a disengaged positionin which rim portion 870 is not engaged with workpiece W. FIG. 22 alsoshows, in phantom lines, an engaged position in which rim portion 870 isengaged with and forms a seal relative to workpiece W. Preferably andadvantageously, electrode contact 858 is maintained in a generallyretracted position within seal 868 when the finger assembly is in thedisengaged position. However, when the finger assembly is moved into theengaged position, seal 868 and rim portion 870 thereof splay outwardlyor otherwise yieldably deform to effectively enable the electrode andhence electrode contact 858 to move into the engaged position againstthe workpiece. One factor which assists in forming the preferred sealbetween the rim portion and the workpiece is the force which isdeveloped by spring 842 which advantageously urges collet 840 and hencefinger 860 and finger tip 858 in the direction of and against thecaptured workpiece. Such developed force assists in maintaining theintegrity of the seal which is developed in the engaged position.Another factor which assists in forming the preferred seal is theyieldability or deformability of the finger tip when it is brought intocontact with the workpiece. Such factors effectively create a continuousseal about the periphery of electrode contact 858 thereby protecting itfrom any materials, such as the preferred plating materials which areused during electroplate processing.

Methods and Operation

[0115] In accordance with a preferred processing aspect of the presentinvention, and in connection with the above-described semiconductorworkpiece holder, a sheathed electrode, such as electrode 860, ispositioned against a semiconductor workpiece surface in a manner whichpermits the electrode to impart a voltage bias and current flow to theworkpiece to effectuate preferred electroplating processing of theworkpiece. Such positioning not only allows a desired electrical bias tobe imparted to a held workpiece, but also allows the workpiece itself tobe mechanically held or fixed relative to the workpiece holder. That is,finger assembly 824 provides an electrical/mechanical connection betweena workpiece and the workpiece holder as is discussed in more detailbelow.

[0116] Electrode 856 includes an electrode tip or electrode contact 858which engages the workpiece surface. A seal is thus formed about theperiphery of the electrode tip or contact 858 so that a desiredelectrical bias may be imparted to the workpiece to enable platingmaterial to be plated the thereon. According to a preferred aspect ofthe processing method, the electrode is moved in a first direction,preferably longitudinally along a movement axis, away from a disengagedposition in which the workpiece surface is not engaged by the electrodetip or contact 858. Subsequently, the electrode is rotated about thesame movement axis and toward an engaged position in which the electrodetip may engage, so as to fix, and thereafter bias the workpiece surface.Such preferred movement is effectuated by pneumatic linkage 825 andpneumatic operator 871 as described above.

[0117] According to a preferred aspect of the invention, the seal whichis effectuated between the electrode member and the workpiece is formedby utilizing a yieldable, deformable seal member 868 which includes arim portion 870. The rim portion 870 serves by contacting the workpiecesurface to form a continuous seal as shown in FIG 8. The preferredelectrode tip is brought into engagement with the workpiece surface byadvancing the electrode tip from a retracted position within the seal orother sheath to an unretracted position in which the workpiece surfaceis engaged thereby. Such movement of the electrode tip between theretracted and unretracted positions is advantageously accommodated bythe yieldable features of the seal 868.

[0118] In addition to providing the preferred electrical contact betweenthe workpiece and the electrode tip, the finger assembly also forms amechanical contact or connection between the assembly and the workpiecewhich effectively fixes the workpiece relative to the workpiece holder.Such is advantageous because one aspect of the preferred processingmethod includes rotating the workpiece about rotor axis 822 while theworkpiece is exposed to the preferred plating material. Such not onlyensures that the electrical connection and hence the electrical biasrelative to the workpiece is maintained during processing, but that themechanical fixation of the workpiece on the workpiece holder ismaintained as well.

[0119] The above described pneumatically effectuated movement of thepreferred finger assemblies between the engaged and disengaged positionsis but one manner of effectuating such movement. Other manners ofeffectuating such movement are possible

[0120] The invention also includes novel methods for presenting aworkpiece to a semiconductor process. In such methods, a workpiece isfirst secured to a workpiece holder. The methods work equally well forworkpiece holders known in the art and for the novel workpiece holdersdisclosed herein.

[0121] In the next step in the sequence, the workpiece holder is rotatedabout a horizontal axis from an initial or first position where theworkpiece holder was provided with the workpiece to a second position.The second position will be at an angle to the horizontal. The angle ofthe workpiece holder to the horizontal is defined by the angle betweenthe plane of the workpiece and the horizontal. In the method, theworkpiece holder is advantageously suspended about a second horizontalaxis which is parallel to the first horizontal axis of the workpieceholder. At this point in the method, the angle between the first andsecond horizontal axes and a horizontal plane corresponds to the anglebetween the workpiece holder and the horizontal. The workpiece holder isthen pivoted about the second horizontal axis to move the workpiece andthe workpiece holder from its initial location to a final location in ahorizontal plane. Advantageously, when the workpiece holder is pivotedabout the second horizontal axis, the first horizontal axis also pivotsabout the second horizontal axis.

[0122] Preferably, during the step of rotating the workpiece holderabout the first horizontal axis, the angle of the workpiece holder withrespect to some known point, which is fixed with respect to theworkpiece holder during the rotation process, is continually monitored.Monitoring allows for precise positioning of the workpiece holder withrespect to the horizontal surface.

[0123] Likewise, during pivoting of the workpiece holder about thesecond horizontal axis, it is preferable that the angle defined by theline connecting the first and second horizontal axes and the horizontalplane be continually monitored. In this manner, the absolute position ofthe workpiece holder (and hence the workpiece itself) will be known withrespect to the horizontal plane. This is important since the horizontalplane typically will contain the process to which the workpiece will beexposed.

[0124] It should be noted that in the above and following description,while the workpiece is described as being presented to a horizontalplane, it is possible that the workpiece may also be presented to avertical plane or a plane at any angle between the vertical and thehorizontal. Typically, the processing plane will be a horizontal planedue to the desire to avoid gravitational effects on process fluids towhich the workpiece is exposed. In one embodiment after the workpiecehas been presented to the processing plane, the workpiece holder isrotated about a spin axis to cause the workpiece to spin in thehorizontal plane. Although not required in all semiconductormanufacturing processes, this is a common step which may be added in theappropriate circumstance.

[0125] The next advantageous step in the method consists of pivoting theworkpiece holder about the second horizontal axis back along the paththat the workpiece holder was initially pivoted along when presentingthe workpiece to the horizontal process plane. There is no requirementthat the workpiece holder be pivoted back to the same position whence itbegan, although doing so may have certain advantages as more fullydescribed below.

[0126] The method advantageously further consists of the step ofrotating the workpiece holder about the first horizontal axis to returnthe workpiece to the position when it was initially presented to andengaged by the workpiece holder. It is advantageous to rotate theworkpiece holder about the first axis in a direction opposite from theinitial rotation of the workpiece holder.

[0127] The advantage of having the workpiece holder terminate at an endposition which corresponds to the initial position when the workpiecewas loaded into the workpiece holder is efficiency. That is, additionalmachine movements are not required to position the workpiece holder toreceive a new workpiece.

[0128] The method more preferably includes the step of rotating theworkpiece holder about the first horizontal axis at at least two supportpoints along the first horizontal axis. This beneficially providessupport and stability to the workpiece holder during the rotationprocess and subsequent movement of the apparatus.

[0129] The method also more preferably includes the step of pivoting theworkpiece holder along with the first horizontal axis about the secondhorizontal axis at at least two support points along the secondhorizontal axis. This beneficially provides additional support for theworkpiece holder while allowing the workpiece holder to be moved in avertical or “Z-axis” direction.

[0130] Importantly, the only motion described in the above method isrotational motion about several axes. In the method described, there isno translational motion of the workpiece holder in a X-, Y-, or Z-axiswithout corresponding movement in another axis as a result of rotatingthrough an arc.

[0131] In compliance with the statute, the invention has been describedin language more or less specific as to structural and methodicalfeatures. It is to be understood, however, that the invention is notlimited to the specific features shown and described, since the meansherein disclosed comprise preferred forms of putting the invention intoeffect. The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A workpiece holder for use in processing a workpiece comprising: a workpiece support; at least one finger assembly mounted upon said workpiece support; said at least one finger assembly including at least one contact for contacting the workpiece; at least one finger actuator operable with said at least one finger assembly for moving said finger assembly between an engaged position wherein said finger assembly is in contact with the workpiece and a disengaged position wherein said finger assembly is disengaged from the workpiece, said at least one finger actuator having means for moving the at least one finger assembly in an axial movement toward and from the workpiece along a longitudinal axis, and means to rotate the at least one finger assembly in a rotational movement about said longitudinal axis; at least one electrode forming a part of said at least one finger assembly, said at least one electrode having an electrode contact for contacting a surface of said workpiece to provide electrical connection therewith, wherein said electrode contact is one of said at least one contact.
 2. The workpiece holder of claim 1 wherein said at least one finger actuator moves said at least one finger assembly in a reciprocal manner.
 3. The workpiece holder of claim 1 and further comprising at least one protective sheath covering at least a portion of the at least one finger assembly to protect the finger assembly from contact with a fluid.
 4. The workpiece holder of claim 1 and further comprising at least one protective sheath covering at least a portion of the at least one finger assembly to protect the finger assembly from contact with a plating fluid, said at least one protective sheath being made from a dielectric material.
 5. The workpiece holder of claim 4 wherein said at least one protective sheath includes a rim portion for engaging said workpiece and forming a seal therebetween.
 6. The workpiece holder of claim 4 wherein said electrode contact is maintained in a generally retracted position within said at least one protective sheath when said at least one finger assembly is in said disengaged position; said electrode contact being moved out of said retracted position when said at least one finger assembly is moved into said engaged position.
 7. The workpiece holder of claim 4 wherein said at least one protective sheath includes a yieldable terminal end adjacent said electrode contact for engaging said workpiece and effectively sealing said electrode contact therewithin when said at least one finger assembly is moved to said engaged position; wherein said electrode contact is maintained in a generally retracted position within said at least one protective sheath when said at least one finger assembly is in said disengaged position; said electrode contact being moved out of said retracted position when said finger assembly is moved into said engaged position. 